5275-5
ADJUSTMENTS
Tone Arm Set-Down
All changers in this series provide automatic posi
tioning for the various sizes of records by "sampling"
the outside diameter of the bottom record resting on the
spindle shelf. The stylus then contacts the record,
after i t has fallen to t h e turntable, approximately
1/16" fron1 the outer edge, o r on a diameter 1/8"
smaller than the original sampling made by the tone
arm.
This adjustment has been accurately set at the factory,
however, should adjustment be required in the field,
a screwdriver adjustment "G" (Figure 5) is provided
in the base plate just forward of the tone arm pivot.
This adjustment consists of an eccentric cam which
contacts Lever "D'' on the Main Cam Gear (See Figure
4).
Rotating this eccentric cam moves Lever "D" i n a
lateral direction and causes the Test Track o n the
Main Cam Gear to become wider or narrower.
The tone arm will s e t down f u r t h e r inward when
the test track is made wider, and will set down on
•
a 1 a r g e r d i a m e t e r when the test track is made
narrower.
Since only one half turn of the Adjustment Screw "G"
covers the entire range of the Set Down Adjustment,
it is suggested that the screw be rotated only a slight
amount at any one time.
It is usually necessary to repeat this adjustment several
times checking the set down position of the tone arm
after each adjustment.
Pickup Muting
The pickup cartridge is muted during change cycle so
that any slight mechanical vibrations of the mechanism
will not be picked up by the cartridge and, therefore,
cannot reach the amplifier input ci1·cuits.
The muting switch is actuated by Lever (141) which
forces the switch contacts to make, sl1unting the pick
up cartridge, as soon as the Main Cam Gear {109)
begins to rotate.
To check that the Muting Switch is breaking properly
proceed as follows:
1. Place any size record on the record spindle. Turn
the c h a ng e r on and allow it to proceed to the
playing position. Turn changer off in this posi
tion.
TEST
TRACK
127
125
1 9 SHUT-OFF
TAB
SHUT-OFF
LEVER
Figure 4--Top View of Sub-Plate Assembly
